Advanced Windows PowerShell Scripting Video Training

Advanced Windows PowerShell Scripting Video Training
Advanced Windows PowerShell Scripting Video Training

Tuesday, September 22, 2009

What loop to use in PowerShell?


PowerShell allows you to control the flow of your scripts through several different looping options. Below are some examples of what types of loops to use.

For loop:

  • Controls execution of code while a condition is true.
  • Usually used to perform a action a certain number of times.

Example:

For ($i = 1; $i –le 10; $i++) {Write-Host “Loop index is at $i”}

While

  • Runs while a condition is true.

Example

$Val=0

while($Val -ne 3)

{

$val++

Write-Host $val

}

Do While

  • Evaluates a condition before running code.
  • If the condition is false, the code will not run.

Example

$Index = 10

Do {$index--

Write-Host "$Index"

} while ($Index -gt 0)

Do Until

  • Evaluates the condition after the code has run once.
  • Loops through the code until a condition becomes true.
  • Ensures that the code will be run at least once before the loop terminates.

Example

$Str = "My Text String"

do {

$str = $str.remove($str.length - 1)

write-host $str

} until ($str.length -lt 3)

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